quagam {lmomco} | R Documentation

## Quantile Function of the Gamma Distribution

### Description

This function computes the quantiles of the Gamma distribution given parameters (α and β) of the distribution computed by `pargam`. The quantile function has no explicit form. See the `qgamma` function and `cdfgam`. The parameters have the following interpretations: α is a shape parameter and β is a scale parameter in the R syntax.

### Usage

    quagam(f, para)

### Arguments

`f` | Nonexceedance probability (0 <= F <= 1).
`para` | The parameters from `pargam` or similar.

### Value

Quantile value for nonexceedance probability F.

### Author(s)

W.H. Asquith

### References

Hosking, J.R.M., 1990, L-moments—Analysis and estimation of distributions using linear combinations of order statistics: Journal of the Royal Statistical Society, Series B, vol. 52, p. 105–124.

Hosking, J.R.M., 1996, FORTRAN routines for use with the method of L-moments: Version 3, IBM Research Report RC20525, T.J. Watson Research Center, Yorktown Heights, New York.

Hosking, J.R.M. and Wallis, J.R., 1997, Regional frequency analysis—An approach based on L-moments: Cambridge University Press.

### See Also

`cdfgam`, `pargam`

### Examples

      lmr <- lmom.ub(c(123,34,4,654,37,78))
      g <- pargam(lmr)
      quagam(0.5,g)

      # generate 50 random samples from this fitted parent
      Qsim <- rlmomco(5000,g)
      # compute the apparent gamma parameter for this parent
      gsim <- pargam(lmoms(Qsim))

[Package lmomco version 0.92 Index]